How the Porsche 917 Works

The Porsche 917 racing car which won Le Mans and was used in the classic film 'Le Mans' (1971) starring Steve McQueen, is displayed during the inaugural Chelsea Auto Legends event on Sept. 5, 2010 in London, England.

Development of the Porsche 917 racecar came about due to a rule change in motorsports. In 1968, the Federation Internationale de l'Automobile, the international racing governing body commonly known as the FIA, announced a new class of racing for sports cars with engines no greater than 5 liters and that weighed at least 1,760 pounds (798.3 kilograms). The decision was made to allow cars with smaller engines to race in the World Sports Car Championship and to attract new companies to the grid [source: Read].

In this new class of racing, only 25 examples of the car had to be built instead of 50, which lowered the cost of entry and production for other manufacturers. Development was headed by an engineer named Ferdinand Piëch, a member of the Porsche family and the chairman of the Volkswagen Group today.

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But when FIA officials visited Porsche's factory to inspect the cars for the 1969 racing season, they found only six examples of the 917, although engineers said they had the parts to build the rest. The FIA said "no way," and mandated Porsche have all 25 cars completed in order to race.

So in just three weeks, Porsche rushed the remaining cars into construction, using secretaries and office workers to quickly assemble the cars in time. They succeeded in building all 25 of the cars, and they passed FIA inspection -- although some of them barely ran and later had to be reassembled and rebuilt by Porsche mechanics [source: Porsche].

Once it started racing, success was not immediate. The car only won one race its first season and was plagued with handling issues. It exhibited wheel spin at 200 miles per hour (321.9 kilometers per hour), and its instability on the track resulted in the death of a driver. Fortunately, John Wyer's Gulf Oil team discovered that adding aluminum sheets to the 917's rear end added some much-needed stability and downforce. Suddenly, the car -- now called the 917K -- became a monster on the racetrack [source: Lieberman].

Before we look at the Porsche 917's racing record, let's learn a little more about the car itself. In this next section, we'll learn about its engine, chassis and how it used novel techniques to keep its weight down.